GPR4 and atrial fibrillation: Compared to AF-MSCs, the gene ontology categories that were more significantly enriched in AF-N-MSCs were gene sets related to the regulation of the cell cycle (SKP2, CyclinA2, CyclinE2, etc.), DNA replication (PRIM1, CDC25A, LIG1, etc.), cell division (CDCAs, KIFs, RCC1, etc.), and chromatin remodeling (CHD7, OIP5, etc.); meanwhile, the genes related to immune system processes (CXCLs, TLR3, TNF, etc.), cell death (CCLs, ICAM1, etc.), response to stimulus (VCAM1, TCF21, ITGA10, etc.), and signal transduction (GPR4, LCP1, SIK1, etc.)were highly downregulated in AF-N-MSCs.